I did the disconnect/reconnect thing and everything up to that point showed up in iTunes. This includes a number of disc to digital transfers I played with last night. There were 2 of note that I know are 4K in iTunes. I did the digital conversion on Hangover blu-ray to HDX and it shows in iTunes on my phone with the 4K mark. Goodfellas - also 4K available in iTunes, I did DVD upgrade to HDX on Vudu. In iTunes now it shows as HD, not 4K. On Vudu, both show as UHD, but only show me as owning the HDX.
Now on the ATV 4K, I just tried playing Hangover and when I swiped down, it showed HD. I started Wonder Woman and when I swiped down, it says 4K. So it doesn't look like I got Hangover 4K. I wish the markings of what you own were a bit more clear. I just played with a few more titles and can confirm that 4K transfers for UHD stuff I own on Vudu. Storks shows 4K and plays in 4K. I don't understand why Hangover shows 4K when I browse but not when I play. While Goodfellas, which has 4K available, doesn't show it when I select it (or obviously when I play it.)
One last thing, since turning on MA, my family sharing of movies is completely worked. When I click on library on any of my kids iPad's under the TV app, it says no purchases (unless I had formerly downloaded something to their iPad.) If I go in the iTunes store, I can go under purchases and select my name and then download movies for them. After this they show up in the TV app for viewing.
4K status doesn't show at all in iTunes. Goofy.
Edit: Looks like if you don't own the UHD in Vudu, you don't get the free 4K upgrade in iTunes. Though in some instances it will LOOK like it when you browse to it on the ATV (Hangover; Live, Die, Repeat), when you play it you only get HD.